City life has interesting effects on mental health — here's how

There are pros and cons to urban living. Shannon Stapleton/Reuters You may have missed it, but 2011 was a watershed year for the human species.

That year, for the first time in history, more than half of the world's human population lived in urban areas.

And the number is expected to rise to two-thirds by 2030, according to a study published in the journal Epigenetics. "This increased urbanity of the world's population has substantial public health implications," the study authors write.

According to the authors of the Epigenetics study, "Nearly a century of research has shown higher risk of mental disorder among persons living in urban versus rural areas." They note research that has found links between certain features of the urban environment, such as "concentrated disadvantage, residential segregation and social norms," that contribute to the risk of mental illness.

But if urban environments are bad for mental health, why do so many urbanites not only survive but actually thrive when living in cities?

Urban living and social connection

"This field of understanding is still in development," Izenberg says. "There are a number of potent pathways between any environment and mental health." For instance, he says a lot of research is currently exploring how an environment, be it natural or man-made, affects the quality and extent of social networks: "How do cities either facilitate or undermine strong communities?" he asks. That, more than the environment itself, may be behind mental health or illness.

He mentions a neighborhood in Boston known as the West End. "It used to be packed, but people who lived there described how they were a community, that everyone knew each other and looked out for each other," he says. "So that was a protective environment in some ways."

Izenberg has studied how race and class affect different community experiences. "Over the last 50 to 100 years, minorities have seen repeated displacement and efforts to undermine those communities," he says. "The ability to foster strong social connections has been undermined, and there is an increasing sense that challenges to communities have resulted in a range of health impacts, from physical conditions like heart disease and poor overall medical outcomes, to social issues like violence and teen pregnancy, to mental health issues like depression and suicide. There is also a lot of overlap among them. Where there is a high rate of violence there is also likely to be higher rates of depression and suicide."

The benefits and risks of urban living

Still, it's hard to prove that urban life "causes" mental illness. There is no denying that urban environments do present more potentially threatening and adversarial social encounters, along with unhealthful stressors like noise and air pollution.

"But it is not so much urban or rural, it's threatening and stressful versus calm and peaceful," Rosenbaum says. "The more it feels like a war zone, the more you are liable to the consequences — anxiety, PTSD, depression. I personally feel that being more crowded and living with more noise and air pollution are in fact more stressful, but I don't know how strong the data is. I know that when I leave New York, I feel a tremendous sense of relief, but I also know others who adapt to it and actually enjoy it."

Those others, in fact, wouldn't live anywhere else, and would find the alleged peace and quiet of suburban or rural life stressful and isolating. "It's not that cities are themselves bad for mental health. In fact, a lot of people argue that there are major benefits for mental health from cities," Izenberg says, including fostering social ties, intellectual and social exchange, exposing residents to different kinds of people and cultures, and even making commuting easier than when driving in from the burbs. "Cities have the potential to be really positive if set up the right way," he says.

One huge problem is that those benefits are not evenly distributed by race or class, he says. Neighborhoods are not equally safe, well-maintained or healthful in terms of pollution, noise, access to fresh food, or outdoor spaces to rejuvenate. "I agree with others who say that we should make cities livable to maximize their benefits," he says. That includes making them a bit less urban. There is plenty of good research showing how beneficial time spent in nature is to mental health.

Even the most steadfast urban dweller can reap the psychological rewards of an occasional walk in the park.